Two rigid bodies $A$ and $B$ rotate with rotational kinetic energies $E_A$ and $E_B$ respectively.  The moments of inertia of $A$ and $B$ about the axis of rotation are $I_A$ and $I_B$ respectively. If $I_A = I_B/4 \,$and$ \, E_A = 100\ E_B$ the ratio of angular momentum $(L_A)$ of $A$ to the angular momentum $(L_B)$ of $B$ is

Find the components along the $x, y, z$ axes of the angular momentum $l$ of a particle. whose position vector is $r$ with components $x, y, z$ and momentum is $p$ with components $p_{ r }, p_{ y }$ and $p_{z} .$ Show that if the particle moves only in the $x -y$ plane the angular momentum has only a $z-$component.

Define angular momentum.

A particle of mass $m$ moves in the $XY$ plane with a velocity $v$ along the straight line $AB.$ If the angular momentum of the particle with respect to origin $O$ is $L_A$ when it is at $A$ and $L_B$ when it is at $B,$ then